Optimisation of Straight Plate Upstream Deflector for the Performance Enhancement of Vertical Axis Wind Turbine at Low, Medium and High Regimes of Tip Speed Ratios

Location and geometry optimisations of Straight Plate Upstream Deflector (SPUD) for performance enhancement of a three-straightbladed Vertical Axis Wind Turbine (VAWT) are carried out at three regimes of tip speed ratios (TSRs). Results analysis reveals that SPUD location has significant effect on the power coefficient (Cp) increment of VAWT. Placing two SPUDs both upward and downward in upstream of VAWT can achieve the highest Cp improvement at all regimes of TSRs. Overall, placing SPUD in upstream of VAWT can improve the Cp value at all regimes of TSRs, but the percentage of improvement can vary. The largest Cp improvement of 126.7% is achieved at low regime of TSRs, while at the medium and high regimes of TSRs, Cp improvements decrease to 52.7% and 52.5%, respectively. Increasing the width of SPUD can increase the average VAWT Cp improvement by 2.83% at all regimes of TSRs.